Expression data from granulocytic MDSC (G-MDSC) and neutrophils. Mus musculus

Myeloid derived suppressor cells (MDSC) playing the immune suppressive roles in tumor bearing host consists of two major subsets of granulocytic and monocytic cells. Granulocytic MDSC (G-MDSC) express CD11b+ Gr-1high Ly6G+ Ly6Clow and produce high level of reactive oxygen species (ROS). Interestingly, neutrophils are well known ROS producing cells during immune defensive process and share same surface markers with G-MDSC. These similar features always brought the fundamental questions what’s the difference between G-MDSC and neutrophils but it’s not yet proven clearly. In this study, we examined the gene expression of G-MDSC and neutrophils using Affymetrix microarray Overall design: G-MDSC (CD11b+Ly6G+Ly6Clow) were purifed from splenocytes in EL4 lymphoma tumor bearing mice by positive selection of Ly6G using microbeads isolation. Neutrophils were purified from ascitic fluids induced after injection of milk protein, casein by negative selection of F4/80 and positive selection of Ly6G using microbeads isolation. Their RNA was extracted and gene expression was analyzed using Affymetrix microarray.

髓系来源抑制细胞（Myeloid derived suppressor cells, MDSC）是在荷瘤宿主中发挥免疫抑制功能的细胞群体，主要包含粒细胞亚群与单核细胞亚群两大主要类别。粒细胞型髓系来源抑制细胞（Granulocytic MDSC, G-MDSC）表达CD11b+ Gr-1high Ly6G+ Ly6Clow表面标志物，且可高水平产生活性氧（reactive oxygen species, ROS）。值得注意的是，中性粒细胞是公认的免疫防御过程中产生活性氧的细胞，且与G-MDSC共享相同的表面标志物。这类相似特征始终引发一个核心问题：G-MDSC与中性粒细胞之间存在何种差异，但该问题迄今尚未得到明确证实。本研究采用Affymetrix基因芯片（Affymetrix microarray）分析了G-MDSC与中性粒细胞的基因表达谱。实验设计概述：从EL4淋巴瘤荷瘤小鼠的脾脏细胞中，通过磁珠分选Ly6G阳性的方式纯化得到G-MDSC（CD11b+Ly6G+Ly6Clow）；从注射牛奶蛋白酪蛋白后诱导产生的腹水中，通过阴性分选F4/80、阳性分选Ly6G的磁珠分选方法纯化得到中性粒细胞。提取两组细胞的RNA后，采用Affymetrix基因芯片进行基因表达分析。